In windy conditions, headset microphones often generate wind-induced noise, or what is often referred to as “wind noise”. Wind noise is undesirable since it disrupts speech intelligibility and makes it difficult to comply with telecommunications network noise-limit regulations.
Various different approaches to reducing wind noise, or countering its effects, are employed in communications headsets. One approach involves subjecting the wind noise to digital signal processing (DSP) filtering algorithms, in an attempt to filter out the wind noise. While DSP techniques are somewhat successful in removing wind noise, they are not entirely effective and do not directly address the source of the problem. DSP approaches also impair speech quality, due to disruptive artifacts caused by filtering.
Another, more direct, approach to reducing wind noise involves using what is known as a “wind screen.” FIG. 1 is a drawing of a conventional headset 100 that has a wind screen 102. The wind screen 102 is placed over the headset microphone, which is typically located at the tip (i.e., the distal end) of the headset's microphone boom 104, to shield the microphone from wind. A typical wind screen 102 comprises a bulbous structure (sometimes referred to as a “wind sock”) made of foam or some other porous material, as illustrated in FIG. 2.
Wind noise can be particularly problematic in headsets that employ short-length microphone booms, as are commonly employed in modern behind-the-ear Bluetooth headsets, such as the Bluetooth headset 300 shown in FIG. 3. Similar to the conventional binaural headband-based headset 100 in FIG. 1, the headset 300 has a microphone boom 302 with a wind screen 304 covering a microphone at the distal end of the boom 302. Because the boom 302 is short, however, when the headset 300 is being worn, the distance between the microphone and the headset wearer's mouth is greater than it is for the conventional headband-based headset 100 in FIG. 1. This requires additional amplification to deliver the correct transmitted speech level to the telecommunications network, but the extra amplification also applies to the wind noise. Given that wind appearing at the microphone is, for the most part, independent of the microphone boom length, the signal-to-noise ratio at the output of the microphone is, therefore, also degraded. So, while the problem of wind noise must be addressed in most any type of headset, it deserves particular attention in headsets that employ short-length microphone booms.
In general, the further a wind screen is separated from the microphone, the more effective the wind screen is at deflecting wind away from the headset's microphone. For this reason, prior art approaches tend to increase the diameter of the microphone boom, either along the boom's entire length, or towards the distal end of the boom, as is done in the behind-the-ear headset 300 in FIG. 3. The increased diameter of the microphone boom provides the ability to increase the separation between the wind screen and the microphone. However, the resulting microphone is often larger and less discreet than desired, and, in some cases, can even be obtrusive and uncomfortable for the headset wearer.
It would be desirable, therefore, to have a microphone boom structure for a communications headset that is effective at reducing wind noise, yet which is also small, discreet and unobtrusive to the headset wearer.